As a user explores the Internet to consume information and make purchases, the user effectively leaves behind a trail of information that can be harvested and used by marketers to create a user profile. A typical user profile consisting of interactions between a given user and that user's computer system enables marketers to analyze user behavior and interests to increase the effectiveness of their marketing activities. For example, via these user profiles, a marketer can determine products purchased by a user, products viewed by a user, a user's sentiment regarding products they have purchased, and whether the user's purchase patterns center on particular brands, types of products, and product price range. By analyzing the user's past online behavior, the marketer can more effectively target users with new products and services that are likely to be of interest to the user and remarket content previously viewed by the user that is likely now to be relevant to the user. However, conventional user profiles are limited in terms of the user activity they cover. For example, most, if not all, “off-line” user activity falls outside the purview of conventional user profiles because such user activity does not involve an interaction with a computer system. Mobile computing devices, such as smart phones, may provide some insight into a user's location while the user conducts certain on-line activities, but even this information is limited to interactions between the user and the mobile computing device. Thus conventional user profiles omit substantial, and potentially valuable, portions of a user activity.